Process for the preparation of diazo derivatives of aminoazo compounds



' Patented May 5, 1925.

, {UNITED STATES PATENT OFFICE.

KARL HEUSNER AND MAX SIMON, LEVERKUSEN, NEAR COLOGNE, GERMANY, AS-

SIGNORS TO FARBENFABRIKEN VORM. FRIEDR. BAYER AND 60., OF LEVERKUSEN, NEAR COLOGNE-ON-THE-RHINE, GERMANY.

PROCESS FOR THE PREPARATION OF DIAZO DERIVATIVES OF AMINOAZO COMPOUNDS.

No Drawing. lTri'gfnal application filed July 24, 1924,

' tion filed February 24,

To all whom it may concern: 7

Be it known that we, 1) KARL HEUSNE-R and (2) MAX SIMON, citizens of Germany, residing at (1) and (2) 'Leverkusen, near 8 Cologne, State of Prussia, Germany, have invented new and useful Improvements in Processes for the Preparation of Diazo Derivatives of Aminoazo Compounds, of which the following is a specification. I

It has been found that the alpha-napththylsulfar'nin'ic acid described by Piria (Ann. 78 (1851) p. 31 onwards) as a thionaphthamic acid (in spite of the presence of a markedly acidic sulfuric acid residue in the .15 amino-group) may be combined with diazocompounds and that the entry of the diazo group occurs almost quantitatively in the para-position to the sulfamino-group. On the other hand it is well known that when 20 using alpha-naphthy-lamine that on the'average from to per cent of the valueless ortho-compound are produced with the para- I compound, according to the choice of the diazotization components and the condition of coupling.

The sulfo-group in these 'sulfaminoazo bodies can easil be split ofi' by warming in aqueous minera acid solution and the roduct further diazotized and coupled wit any so desired couplin component. The diazo bodies so obtaine are of considerably higher value and of greater purity inasmuch as the first combination of the'naphthylsulfaminic acid with the. diazo compound has occurred substantially in para-position only to the sulfamino-group. It has further been found that the so-called sulfaminoazo compound need not be first saponified for the purpose of further diazotization but that the 40 splitting ofiof the sulfo-group and the diazotizatlon may be carried out in a single operation. It is, therefore, not always necessary to isolate the sulfaminoazo compounds but in many cases the splitting off of the sulfo- 4.5 group, diazotization and the coupling can be directly performed in one operation. The

thylsulfaminate and 20 parts of 1925. Serial 1T0. 11,349.

process proceeds practically quantitatively. The reaction proceeds as follows:

fully the following example is given; the parts bemg by weight:

Example: 17.3 parts of meta-sulfanilic acid are diazotized and coupled with a solution of 24.5 parts of sodium-alpha-naph- 100 per cent sodium acetate at about 10 CT The coupling is completed after several hours stirring and a clear brown-yellow solution results. 100 parts of hydrochloric acid (19 Be.) is added to this solution and heated for a short while. The aminoazo body formed is filtered ofi, suspended in water anddiazotized with 10.5 parts sodium nitrite-in hydrochloric acid. I

Instead of saponifyin and isolating the amlnoazo bodies it is a so possible to proceed as follows:

The brown-yellow solution obtained above is acidified at about 15 C. with 70 parts of hydrochloric'acid (19 B.) and treated with a solution of 10.5 parts of sodium nitrite. The unsaponified aminoazo body separates at first by the action of the acid as a dark colored mass but goes into solution on addition of sodium nitrite with a yellow color. After short stirring the separation of the diazo-compo'und begins. As soon as the separation is com lete the diazo body produced isfilteredo and may be con led in the customary manner with any desired dyestuif com onents.

The formation 0 the diazo compound Serial No. 727,984. Divided and this applicatakes place practically quantitatively, calculated on the meta-sulfanilic acid whereas without using the sulfaminic acid the diazo compound obtained "from the coupling product of meta-diazo-benzene, sulfonic acid and alpha-naphthylamine leads only 'to a yield Instead of meta-sulfanilic acid other sul= fonated, carboxylated and substituted derivatives of the benzol, naphthalene, anthracene, anthraquinone and diphenyl series may be used. Furthermore, unsulfonated and non-carboxylated compounds of the aforementioned kind are just as suitable for this process. mong such products we mention aniline, aminophenolethers, monoacidylphenylenediamines, chloranilines and their homologues, alphaor beta-naphthylamine, diaminodiphenyl derivatives, the homologues of these amines, etc.

Trisazo-compounds may also be prepared by further coupling of these diazo bodies with alpha-naphthylsulfaminie acid, saponification, diazotizatlon and further coupling.

som

The above described process of diazotizing sulfaminoazo compounds without previous saponification can also be carried out on the fibre. Dyestuffs prepared from benzidine derivatives with alphanaphthylsulfaminic acids are substantive, that is to say have direct affinity to vegetable 'fibres; in "this case it is possible to diazotize cotton material dyed with these goods by treating same directly with diluted mineral acids and sodium nitrite. The diazo compounds afiixed to the fibre are then developed in known manner.

The present application is a division of application No. 7 27 ,984 filed July 24, 1924.

We claim:

1. In processes of preparing alpha-diazonaphthalene-alpha-azo compounds the steps comprising coupling diazo compounds with alpha-naphthylsulfaminic acids, splitting off the sulfo-group of the naphthvlsulfaminic acid and diazotizing in acid solution with alkali-metal-nitrites.

2. In processes of preparing alpha-diazonaphthalene-alpha-azo compounds, the steps comprising coupling a diazo compound with alphanaphthylsulfaminic acid and treating same in aqueous solution with an acid and an alkali-metal-nitrite.

3. In processes of preparing alphadiazonaphthalene-alpha-azo compounds, the steps comprising coupling a diazo compound with alphanaphthylsulfaminic acid and treating same in aqueous solution with a mineral acid.

In testimony whereof we have hereunto set our hands.

KAKL HEUSNER. MAX SIMON. 

